Bug 901106 - Make sure sure the nsDOMScriptObjectFactory gets instantiated.

This used to happen implicitly when we created the first nsJSContext, but that
goes away in the next patch. Without this, we get a couple of odd exception-
related failures in the IPC indexedDB tests.

dom/base/nsJSEnvironment.cpp

@@ -2748,6 +2748,8 @@ NS_DOMStructuredCloneError(JSContext* cx,
   xpc::Throw(cx, NS_ERROR_DOM_DATA_CLONE_ERR);
 }
 
+static NS_DEFINE_CID(kDOMScriptObjectFactoryCID, NS_DOM_SCRIPT_OBJECT_FACTORY_CID);
+
 //static
 nsresult
 nsJSRuntime::Init()
@@ -2857,6 +2859,15 @@ nsJSRuntime::Init()
   obs->AddObserver(observer, "memory-pressure", false);
   obs->AddObserver(observer, "quit-application", false);
 
+  // We need to explicitly get the nsIDOMScriptObjectFactory service in order
+  // to force its constructor to run, which registers various exceptions
+  // providers and other things. It would be nice to make this more explicit
+  // and less side-effect-y.
+  nsCOMPtr<nsIDOMScriptObjectFactory> factory = do_GetService(kDOMScriptObjectFactoryCID);
+  if (!factory) {
+    MOZ_CRASH();
+  }
+
   sIsInitialized = true;
 
   return NS_OK;